The present invention relates to a gas heating apparatus for heating a gas to a high temperature.
There is generally known in the prior art a heat exchanger type heating apparatus in which a gas to be heated is contacted to a wall structure heated to a high temperature.
In this type of gas heating apparatus, it is required to provide a large heat transfer surface of the wall structure or to provide a large temperature difference between the wall structure and the gas due to the low coefficient of thermal conductivity between the higher temperature wall structure and the gas. Thus, it is extremely difficult to realize a compact structure of the gas heating apparatus.
In order to improve such defect, certain gas heating apparatus having a ceramic cylinder, in which an electrically heated heat generating means is disposed so as to enlarge the heat transfer surface, is already known.
In general, from the view point of energy efficiency, it is not preferable to generate whole energy for heating gas only by means of a simple electrical heater over the entire range of temperature. In the conventional gas heating apparatus it using an electric heater, it an extremely big size of apparatus is required in order to obtain the higher temperature gas, such as over 1,000.degree. C., and, thus, it is not so practical.